Substance abuse by individuals with schizophrenia has reached epidemic proportions, yet little is known about why they use substances or how they can be helped to decrease use. The most widely accepted conceptualization of their substance abuse treatment needs is adapted from Prochaska and DiClemente's Transtheoretical Model (TTM). This model has proven to be quite robust in explaining the process of change in a variety of less impaired substance abusing populations, and several instruments have proven to be reliable and valid for assessing central components of the model. However, the TTM assumes intentional behavior change and full participation in the process of change by the substance abuser. Schizophrenia is marked by a number of symptomatic, neurocognitive, and psychosocial characteristics that would make it difficult for many individuals to successfully perform these complex activities, thereby raising questions about the applicability of the model for this population. Notably, patients with schizophrenia have significant impairments in cognitive function, including attention, memory, and higher level "executive" abilities, that may limit their ability to analyze the pros and cons of substance use, retain a focus on goals for decreased use over time, and form realistic efficacy expectations based on past experience. The disorder also is frequently associated with avolition and anhedonia, which may interfere with the ability to sustain motivation to reduce use. The overall purpose of this project is to examine attitudes about substance use, motivation to reduce use, and the process of change among schizophrenia patients who meet DSM-IV criteria for current Cocaine Dependence or are in Early Remission. The specific focus is the validity of the TTM for this population, and the adequacy of the standard measures of stages and processes of change developed for less impaired groups. Four groups of subjects will be assessed at Baseline, 3-, 6-, 9-, and 12-months: 70 Schizophrenia patients with current Cocaine Dependence, 70 Schizophrenia patients who are in Early Remission from Cocaine, 70 patients with Major Depression and current Cocaine Dependence, and 70 patients with Major Depression who are in Early Remission from Cocaine.